1. Field of the Invention
The present invention generally relates to Internet and telephonic communications, and in particular, to a method and system to provide a single telephone number for geographically dispersed telephony service subscribers.
2. Description of the Related Art
Call waiting service provided by telephone companies enables telephone users to accept or ignore an incoming telephone call when the user is talking to another person over the telephone line. Because telephone lines are often used to access the Internet in addition to making voice calls, Internet call waiting (ICW) services are provided to enable subscribers to receive incoming telephone calls even when the subscriber's telephone line is being used to access the Internet.
Gateway servers, such as Internet Protocol (IP) telephony gateways, may be used to provide ICW services. ICW service center may employ a number of gateways connected between the Internet and the Public Switched Telephone Network (PSTN) via telephone trunk lines, such as Integrated Service Digital network (ISDN) Primary Rate Interface (PRI) lines. Typically, each of the gateways is assigned to service a predefined group of subscribers. In some implementations, subscribers are partitioned geographically (e.g., by the area code of the subscriber's telephone number).
Typically, ICW service providers will assign a telephone number for each of the gateways. This means that if the ICW service provider has four gateways to service its subscribers, there will be four separate telephone numbers assigned to the four gateways. Because each subscriber is preassigned to a particular gateway, subscribers are required to program their call forwarding function to forward their telephone calls to the telephone number corresponding to the gateway they are assigned to. As a result, subscribers in certain predefined region will be assigned a certain telephone number while subscribers in another region will be assigned a different telephone number.
There are a number of problems associated with such conventional ICW architecture. For example, if for any reason subscribers are reassigned from one gateway to another gateway (e.g., perhaps because the area code of their telephone number changed), the subscribers are required to reprogram their call forwarding service to forward their incoming call to a different telephone number, which introduces opportunity for user error. Further, the conventional ICW architecture does not provide for service redundancy in the event that one of the gateways fails, or one of the PRI lines coupled to gateways fails.